


Reason in Madness

by Sincestiel



Series: Tumblr Prompts [17]
Category: Supernatural
Genre: Anal Fingering, Anal Sex, Double Penetration, Felching, M/M, Multi, Rimming, Sibling Incest, Tumblr Prompt
Language: English
Status: Completed
Published: 2017-01-19
Updated: 2017-01-19
Packaged: 2018-09-18 14:28:42
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,106
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9389201
Author URL: https://archiveofourown.org/users/Sincestiel/pseuds/Sincestiel
Summary: He sounds so utterly and completely fucked out already.  Like the time he spent making out with Dean while Sam prepped him has left him frayed and satisfied despite the fact that he’s hasn’t even come yet.  And Sam really wants to give him what he wants.  But he just doesn’t think it’s going towork.  He keeps looking at Castiel’s hole, already stuffed to capacity and his own hard cock and it seems too impossible.





	

**Author's Note:**

> Written for this prompt: I wondered if you could do Dean/Sam/Cas where Cas gets DP by the boys? With lots of fluff/aftercare too :)
> 
> I hope this is satisfactory!

_There is always some madness in love. But there is also always some reason in madness._

\- Friedrich Nietzsche

“Fuck, Cas,” Sam murmurs, his hand splaying over the top of Castiel’s bare back and then dragging down to rest over the swell of his ass. God he looks so good sprawled out over Dean’s body, Dean’s hands gripping his hips and holding him still so Sam can see where their bodies are joined.

He’s stretched so wide already just to accommodate Dean’s dick, the ring of muscle resting snug around Dean’s base is thin and clinging tightly to the cock spearing him. And every time Sam traces a fingertip over his rim, Cas shivers and moans and Sam just can’t imagine that he can take any more. Dean isn’t a small guy, not by a long shot. But Sam is bigger. And that hole is so tiny and already stretched wide and loose.

“He can take it, Sammy,” Dean rasps, his lips pressed to Cas’ temple as one hand moves up to run soothingly up and down Castiel’s back, leaving gooseflesh in its wake. “Can’t you, Cas? Been wantin’ it, haven’t you?”

Cas groans and nods. His lips catch on Dean’s collarbone as he says, “Yes. Sam. Please.”

He sounds so utterly and completely fucked out already. Like the time he spent making out with Dean while Sam prepped him has left him frayed and satisfied despite the fact that he’s hasn’t even come yet. And Sam really wants to give him what he wants. But he just doesn’t think it’s going to _work_. He keeps looking at Castiel’s hole, already stuffed to capacity and his own hard cock and it seems too impossible.

Dean must catch on to Sam’s hesitance, because he whispers something to Castiel and then his legs bend and he slowly spreads them wide, effectively opening Castiel’s body as much as he can to Sam’s gaze. Dean, with his newfound leverage, lifts his hips and encourages Castiel to arch his back, and there’s Castiel’s entrance and Sam can’t help himself.

He scoots back a little and then leans over. And the fact that he’s never been this close to Dean’s dick doesn’t even register. Without warning either of them, he starts right where Dean’s balls meet his cock and then licks all the way up to the top of Castiel’s crack. They moan in unison and, surprising Sam, it’s Dean who says, “Again, Sammy. Start lower, baby.”

Sam has to compose himself before he can do anything other than whimper and reach down to palm at his own erection. He rests his forehead on Castiel’s hip and just breathes a few times, filling his lungs with a mixture of Castiel and Dean that he never wants to relinquish.

The next time Sam moves in with his mouth, he sucks softly at each of Dean’s balls before lapping up and over both of them again. Dean sobs, his legs giving out momentarily and lowering them both back to the bed. But when Sam pats his thigh, urging him back up, he complies and shudders hard when Sam dips back down to tongue and suckle at his sac. And then he drags his tongue up again, this time stopping to work at Cas’ opening. 

He tastes sweat and lube and some unidentifiable flavors that must be unique to the activity – something he’s never done before – or Cas and Dean in general. It’s a little unpleasant, but the sounds they’re making for him are not. He delves deeper, bringing a finger in to play. And when he manages to get both his tongue and his finger in alongside Dean’s pulsing cock, he starts to think this might actually work.

Sam leans back and fishes around in the sheets for the bottle of lube. He squeezes out a generous amount over the top of Cas’ ass so that it slowly runs down over his finger as he works it in and out. And when he works another one between Dean’s dick and the taut muscle, Cas squirms and Dean breathes out a shaky, “Yeah, Sammy. ‘S good.”

It takes several minutes, a lot of lube, and endless encouragement from both Dean and Sam, but eventually Sam gets Cas loosened enough that he thinks he might be able to get the head of his dick in. And god is he glad because he’s throbbing with need. He thinks if he can get past the first bit of resistance, the rest should sink right in. Hopefully.

“Should I wear a condom?” Sam asks, not really sure what the plan is here. Dean’s bare, but he and Cas have been fucking for a while, and as far as Sam knows, they’re exclusive. Or they were until now.

“Up to you, Sammy,” Dean says just as Cas moans, “God no.” And Dean chuckles and pats Cas on the head before he tangles his fingers in that unruly hair and tilts Cas’ head enough to kiss his lips softly.

“Don’t be so demanding, Cas. Let Sam decide. Gonna be good for you either way, okay, sweetheart?” Cas nods, but he cuts his eyes as far as he can and gives Sam a petulant look. So Sam knees up between Dean’s spread thighs and then all the way against the back of Cas’, no condom in sight. Cas grins. Whatever. It isn’t like Cas can’t heal them or wouldn’t already know if one of them had something.

When Sam reaches down to line himself up, he attention hangs on Dean’s lips and the way his tongue moves over them just as the head of Sam’s dick brushes over his balls. There’s heat in Dean’s eyes like Sam’s never seen before. Not directed at him anyway. He makes a mental note to corner Dean later and find out just how long he’s wanted this. And then, when Dean’s teeth sink into that beautiful, full bottom lip, Sam makes another note to taste it for himself at the first opportunity.

Sam prods carefully at Castiel’s hole, lining his dick up with Dean’s and trying to work in alongside him. He has to use his other hand to run around Cas’ rim and stretch him out just enough to get the very tip of his head in. He’s moving very slowly, trying to be mindful of Cas’ body and the limits it might have, but Castiel is impatient.

“Come on, Sam,” he grunts, wiggling his hips as much as he can where he’s trapped between their larger bodies. Sam presses forward, wincing in sympathy when the head of his cock pops in suddenly. The sharp gasp that comes from Castiel has both their hands petting over his trembling body.

“Shh, that’s good, sweetheart,” Dean shushes into Cas’ ear, though his eyes are still locked on Sam. “Got both of us in you. Just what you wanted, huh? Wanted us to fill you up, make you ours? Feels fucking awesome, Cas. So perfect, right Sammy?” Dean kisses gently at the side of Cas’ head.

“Yeah, god, yeah,” Sam replies, still thrumming with little shockwaves of pleasure as he adjusts to the feel of Cas’ ass squeezing into him from the top, and Dean’s dick snug against the underside of his cock. Dean’s legs come down and out, falling over the tops of Sam’s thighs and he focuses on the feel of Dean’s hair catching against his own. It’s fucking surreal, having both Dean and Cas under him.

Sam inches forward, pressing more of himself into Cas’ body and the moan Cas releases is one of the sweetest sounds Sam’s ever heard. Like it’s too much for him to handle. Like he can’t take even another centimeter of the dick Sam’s feeding into him. But also like he wants it so bad he can’t stand that it’s not all the way in. Like he might die if Sam doesn’t bury himself all the way and soon.

“Fuck, Cas, you like it? Need me to stop?” Because Sam will. It might fucking kill him to lose the heat of both of them around his pulsing, needy dick, but he really will pull out if that’s what Cas needs.

“No, Sam, please. Just. Come on. All the way.” His voice is strained and he is so out of it he doesn’t even sound capable of completing his sentences. He’s not telling Sam to stop, but Sam doesn’t know him as well as Dean, so he pulls his eyes off of the side of Castiel’s pleasure slack but flushed and sweaty face. 

When he meets Dean’s gaze Dean nods, urging him to get on with it. And when Sam still doesn’t move, Dean hooks his feet the best he can around Sam’s back and tugs him forward. He sinks the rest of the way in on a groan and only realizes the sound is coming from him when he’s fully seated.

For several long, drawn out seconds, Sam doesn’t move. Cas is quivering between them and he feels more than hears the little whimpers falling from him and he’s so close, so fucking close, to calling this whole thing off despite how much his dick is going to hate him. But then Castiel sighs and tilts his head to press his lips against the inside of Sam’s bicep where it’s holding him up beside their heads. It’s soft and tender, intimate in a way even the melding of their bodies isn’t, and Sam nuzzles into the center of Cas’ back between his shoulder blades and returns the gesture.

And there must be something about seeing such open and honest affection between the two of them that really does it for Dean. The sound he makes is almost pained, jittery and urgent, and one of his hands finds its way up and into Sam’s hair. And then he’s tugging. It’s a stretch, even with the few inches of height he has on both of them, but somehow, Dean manages to guide Sam’s mouth to his over Cas’ shoulder.

The kiss they share is careful, nervous and unsure at first. Dean’s tongue teases at his top lip and when Sam’s mouth parts he feels Dean’s grunt against his tongue. It’s so awkward but so goddamn delicious. Something he never knew he wanted but doesn’t want to ever live without now that he’s had it. And fuck, he can’t wait to spend hours mapping his brother’s mouth. But the strain from being pulled taut over Cas’ body is too much, and he relents after just a small taste.

He doesn’t get far though, because Cas’ face is right there and his mouth is so tempting. Sam nips at the bottom lip, and it’s even more plump and inviting than Dean’s. God, Sam can’t even imagine what kisses between the two of them must feel like, what with their gorgeous full lips. Cas whines, inspiring Sam to push forward with a firmer kiss and he feels Cas’ smile grow under his ministrations.

When he pulls away, Cas’ blue eyes are dazed and his expression is almost giddy. He’s euphoric and it occurs to Sam that maybe Cas has wanted this, to be sandwiched between the two of them, for quite some time.

“Move, Sam,” Cas whispers into the barely there distance between their faces, “I would like to feel you move.”

That’s really all the incentive Sam needs. He levers himself up, once again bracing on his arms. He pulls almost all the way out, slowly but steadily. And then, he looks into Dean’s lust blown eyes, and rolls his hips inward, filling the vacated spot completely with one fluid movement.

Cas contracts around him like a vise and Sam actually feels Dean’s dick throb and jump. He’s not sure which one of them is shaking harder or who’s panting the most, but he doesn’t think it matters. The look on their faces, eager and flushed with need, tells him all he needs to know. No one, himself included, wants to stop.

And so he repeats the motion. Over and over again until Cas is begging under his breath for someone to just please let him come and Dean is frantically struggling to get a hand between their bodies with Sam weighing Cas down. Sam gets an arm under Cas’ chest and lifts just enough for Dean to wedge his hand between them. 

He sucks and nibbles at the side of Cas’ neck as Dean’s hand closes over Cas’ erection and it is a matter of milliseconds before Cas’ channel starts to pulse and flutter around them. Sam can just see the first spurt of Cas’ come splashing over Dean’s ribs and that’s it. He loses it.

White hot pleasure shoots up his spine and every nerve ending in his body sparks as his hips drive forward, losing all rhythm. He spills for what feels like forever into Cas’ body and he only realizes that Dean is coming too when the last few aftershocks are wracking his body, causing him to jerk and fall free of Cas’ ass.

He lies there, starfishing over the top of both of them, one arm trapped between their overheated bodies, until Dean grunts and starts grumbling about not being able to breathe. Then he pulls himself up and his eyes are drawn down to where Dean and Cas are still connected. The sight sends another jolt of desire through him and he has to remind himself he’s not a teenager anymore and his refractory time is a little longer now.

Dean is still partially hard and halfway buried inside of Cas. That’s hot, but it’s not the part that has Sam licking his lips. No, the best part is the way their come, his and Dean’s mixed together, is slowly leaking out of Cas to run down over Dean’s shaft. He follows the path of one drop in particular as it winds its way over the wrinkled landscape of Dean’s sac. 

Sam’s never had a fascination with bodily fluids before. He’s never really wanted to taste come, his own or anyone else’s. But right now all he wants is to press his mouth over that ever shrinking space between Cas’ asshole and Dean’s dick and suck. He wants to lap at where they’re connected until the only thing left to taste is skin.

He loses the battle with himself and bends over, catching that errant drop of come that’s about to slip off Dean’s body and be lost in the sheets. It’s bitter and unpleasant but the choked whimper that bursts out of Dean is worth it. But when his tongue traces up, over Dean’s cock and then around Cas’ hole again, the lube taste now mixed with the salty chlorine taste of come, Dean shivers and whines in a not so happy way. 

“Sensitive,” he offers by way of explanation, shaky and apologetic. Sam just smiles and turns his head to kiss at Dean’s inner thigh once before he sits up again. 

When Dean smiles at him, sated and utterly relaxed, a look Sam’s never seen on his fast so fresh before, Sam’s heart skips a beat. God, maybe he should figure out how long he’s wanted this before he tries to make Dean give up his secrets. Because that feeling in the pit of his stomach? That’s not anything new even if he didn’t really cotton on to it before all this.

Sam stands on protesting legs and makes his way down the hall to get a wet wash cloth. When he returns, Dean and Cas have shifted so that they’re on their sides facing each other. They’re trading sloppy, sweet kisses and the moment is so achingly tender, Sam hates to interrupt. So he stands in the doorway as Dean fawns over and praises Castiel.

“You did so good, sweetheart,” Dean whispers, in a voice that, until this point, Sam has only ever heard directed at him. He thinks, maybe, if they hadn’t just included him, he might be jealous. But, as it is, he just finds it incredibly endearing. He didn’t really think Dean had it in him to be so gentle with anyone who isn’t Sam. 

“God, you’re so good for me,” Dean says and there’s something about the way he says it. Sam knows it’s not a new discovery, that Cas is pretty much perfect for Dean in every way, but he still sounds awed by it.

Dean pets over Cas for a few more minutes, dropping kisses all over his face and neck, their bodies still intertwined if no longer joined. And Sam finds it harder and harder to breathe watching the physical manifestation of their love. Because, if he had any doubts before, now he doesn’t. They’re not just fucking. Nowhere near it.

He’s just about to slip away and leave them to it, a weird sinking feeling in his gut at the thought that maybe they only intended it to be a one-time thing. A little no-strings comfort in their always changing and dangerous lives. But then, without turning his head from Dean’s attention, Cas reaches out to him. And when Dean notices the movement, he pulls away and gives Sam that smile again. The one he leveled Sam with just before he guided Cas to straddle him in the kitchen before they stumbled their way to the bedroom. It’s equal measures naughtiness, heat, and nerves. Sam thinks it’s his favorite version of Dean’s smile.

He joins them again, helping Dean get Cas cleaned up and then slotting in behind him, arms around Castiel’s waist, while Dean perfunctorily wipes himself clean and then throws the cloth somewhere off the bed. Then they box Cas in, trading kisses over the top of his head before moving down to pepper them over whatever parts of him they can reach.

It’s almost as good as the sex, cuddling Cas between them, hands and bodies brushing at different points of contact as they work together to ease Cas into sleep. They work as well together in this as they do in battle and Sam is pleased to find that there’s nothing remotely odd about the way Dean’s hand reaches out to close over his naked hip once Cas is breathing evenly over Dean’s collarbone.

He doesn’t say anything. Not with his voice. But his watery green eyes speak volumes and Sam knows this has been a long time coming. He leans in for a soft kiss, Cas’ messy hair tickling his chin as he does. And then he settles into his pillow, holding Dean’s gaze as long as he can before sleep takes him.


End file.
